python-firebase-gae is a python wrapper for Firebase's REST API that was produced specifically to run in the Google App Engine enviroment (doesn't use the requests library). It uses urlfetch.
Some alternatives include
Both of which use the requests library.
Clone it into the /lib/firebase folder:
$ git clone http://github.com/benletchford/python-firebase-gae lib/firebase
Import it:
from lib.firebase.wrapper import Firebase
Instantiate it:
ref = Firebase('https://example.firebaseio.com/users')
Or with authentication:
ref = Firebase('https://example.firebaseio.com/users', 'auth-token')